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From Patrick Hunt <ph...@apache.org>
Subject Re: Dynamic adding/removing ZK servers on client
Date Mon, 03 May 2010 19:22:32 GMT

On 05/03/2010 12:07 PM, Dave Wright wrote:
>> Yes, that's what I meant - we could update the ZK client lib to do this. It
>> would be invisible to the client application (your code) itself.
> I don't think that's a bad idea, and the general approach in ZK-146 of
> using an interface that gets called to retrieve the list of hosts
> seems good (so that you aren't tied to a specific implementation of
> hosts lists, be it HTTP or DNS). That said, I don't think the actual
> implementation of ZK-146 is a good solution, since it only resolves
> the host list once. An implementation that resolved it on each
> disconnection would be better but require deeper changes to the
> ClientCnxn.

You could update 146 as appropriate, handling changes to the ensemble 
members wasn't an original goal. Notice there was some discussion on how 
to do this in a way that would be as flexible as possible going forward, 
and so that we don't end up with all kinds of constructors (etc...) on 
top of ZK client for the different schemes. That is still a concern, 
something that we should come to agreement on before implementation is 
started I mean.


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